I have a 69 with a 95 LT1. It's my understanding the stock pump is 43 psi.

I've been looking at a the GM32BFI tank. It comes with a 85-115 psi 50-60gph pump.
WIll this work?

The engine is stock.

 

That'll work because you are going to regulate the fuel pressure down to ~43 anyway - The stock LT1 pumps will make higher pressures like that too if you clamp off the return line so its not like the LT1 pump only makes 43#, that's just what it's regulated at. You can't put 100# to your injectors, at least not for very long.